Biologics Feature

Human Stem Cells Grown on Plants

Biloine W. Young • Thu, April 6th, 2017

William L. “Bill” Murphy, M.S., Ph.D., a professor of biomedical engineering at the University of Wisconsin, Madison, creates tiny scaffolds made of plastic or rubber on which he grows human stem cells.

To grow clusters of human stem cells that mimic organs in the lab and might be used someday in tissue implants, Bill Murphy, has, in the past, created tiny scaffolds for the cells made of plastic or rubber.

The task of the three-dimensional scaffolds is to support the cells, feed them, help them organize and allow them to communicate.

One spring day in 2014, Murphy looked out his office window onto the university’s Lakeshore Nature Preserve, and saw structures that do those very things naturally: plants.

Now, three years later, Murphy and Gianluca Fontana, a UW-Madison post-doctoral fellow, have grown skin, brain, bone marrow and blood vessel cells on cellulose from plants such as parsley, spinach, vanilla and bamboo.

Plants could be an alternative to artificial scaffolds for growing stem cells, the researchers reported in their article on their work in the journal Advanced Healthcare Materials.

“Rather than having to manufacture these devices using high-tech approaches, we could literally pick them off of a tree,” said Murphy, co-director of the UW-Madison Stem Cell and Regenerative Medicine Center. He said that the strength, porosity and large surface area of plants could prove superior to making scaffolds than are the current methods, using 3-D printing and injection molding.

“Plants have a huge capacity to grow cell populations,” Murphy said. “They can deliver fluids very efficiently to their leaves…. At the microscale, they’re very well organized.”

There are many species of plants to choose from. After Murphy’s inspirational gaze out the window, he and Fontana tested plants as scaffolds for stem cells using varieties they could easily obtain: parsley, spinach, jewelweed, water horsetail, summer lilac and softstem bulrush.

Then Fontana asked John Wirth, Olbrich Biotanical Gardens’ conservatory curator, about other species that might work. Wirth invited Fontana to walk through the tropical greenhouse and take samples back to his lab.

“I had never had a request like this before; it made me look at plant material in a different way,” Wirth said. “I think it’s a fantastic way of using these pieces of living tissue, to grow human tissue.” Olbrich plants that proved useful include vanilla, bamboo, wasabi, elephant ear, zebra plant and various orchids.

Leave a Reply

3-D Printer Plus Stem Cells Equals Cartilage

Biloine W. Young • Thu, August 15th, 2013

With the help of a 3-D printer, scientists in Melbourne, Australia, report that they have grown human cartilage from stem cells. Led by Associate Professor Damian Myers of St. Vincent’s Hospital, scientists developed the 3D scaffolds which were used to grow the cartilage cells. Myers claimed that this was the first time true cartilage had been grown, according to Lisa Wachsmuth of the Illawarra Mercury.

"We basically take fat cells from behind the knee cap, and then we isolate the stem cells from the fat tissue, " Myers said. "We are differentiating, or actually forcing the stem cells to become cartilage cells within the 3D scaffolds and we form cartilage tissue by doing that.”

Myers said that they were performing the experiment in the laboratory with the anticipated next step being to start testing in a pre-clinical model. "Hopefully over the next three to five years we can advance that for use in humans, for cartilage repair, " he said. He believes that this process would benefit those with traumatic injuries from accidents, sporting injuries or certain conditions or diseases like osteoarthritis.

One Stem Cell Fact You Need to Know

Biloine W. Young • Wed, September 24th, 2014

Everyone who works with stem cells knows that human pluripotent stem cells can become any of the 220 cells in the body. Undifferentiated cells are influenced by the chemicals in the lab dish in which they are grown. By using different chemicals, researchers can direct the cells to become whatever kind of cells they want.

Terry Devitt, writing for University of Wisconsin News, reports that something other than the chemicals in the petri dish affects cell differentiation. The hardness of the surfaces on which stem cells are grown also exerts a profound influence on the cells’ fate.

“Investigators use soluble growth factors to get the cells to differentiate, ” explained Laura Kiessling, Ph.D., a UW-Madison professor of chemistry and biochemistry and stem cell expert. She and her associates grow stem cells in plastic dishes coasted with a gel that may contain as many as 1, 800 different proteins. She says that, whether or not the gel contains proteins, the cells are always working at becoming something—but in seemingly random ways.

Kiessling, noting that cells appeared to react to the surfaces near to them, decided to find out if the quality of a surface mattered to a stem cell. According to DeVitt, her group created gels of different hardness to mimic muscle, liver and brain tissues. They also wanted to find out if the surface alone, without any added proteins or chemicals, would influence cell fate decisions and have an effect on differentiation.

The results, Kiessling reported, showed that a soft, brain tissue-like surface, independent of any soluble factors, was catalyst enough to direct cells to become neurons, the large elaborate cells that make up the central nervous system. “We didn’t change anything but switch from a hard surface to a soft surface, ” Kiessling says. “They all started looking like neurons. It was stunning to me that the surface had such a profound effect.”

Devitt reported that the Wisconsin researchers believe that the mechanical properties of a surface are influencing a protein called YAP. YAP is found in the cytoplasm and the nucleus of a cell, and when it is in the nucleus, YAP regulates gene expression.

Recipe For Missing Bone: Found!

Elizabeth Hofheinz, M.P.H., M.Ed. • Thu, May 12th, 2016

A team from The Johns Hopkins University has found a way to use manmade plastic to create a framework for filling in missing bone. According to the May 4, 2016 news release, it involves mixing at least 3% pulverized natural bone with the plastic and creating the necessary shape with a 3D printer.

Warren Grayson, Ph.D. associate professor of biomedical engineering at the Johns Hopkins University School of Medicine was the report’s senior author. He and his team used polycaprolactone, or PCL, a biodegradable polyester used in making polyurethane that has been approved by the FDA for other clinical uses.

To strengthen the PCL, they mixed it with increasing amounts of bone powder, made by “pulverizing the porous bone inside cow knees after stripping it of cells.”

“After three weeks, cells grown on 70% bone powder scaffolds showed gene activity hundreds of times higher in three genes indicative of bone formation, compared to cells grown on pure PCL scaffolds. Cells on 30% bone powder scaffolds showed large but less impressive increases in the same genes.”

“After the scientists added the key ingredient beta-glycerophosphate to the cells’ broth to enable their enzymes to deposit calcium, the primary mineral in bone, the cells on 30 percent scaffolds produced about 30 percent more calcium per cell, while those on 70 percent scaffolds produced more than twice as much calcium per cell, compared to those on pure PCL scaffolds.”

“Finally, the team tested their scaffolds in mice with relatively large holes in their skull bones made experimentally. Without intervention, the bone wounds were too large to heal. Mice that got scaffold implants laden with stem cells had new bone growth within the hole over the 12 weeks of the experiment. And CT scans showed that at least 50% more bone grew in scaffolds containing 30 or 70% bone powder, compared to those with pure PCL.”

Dr. Grayson told OTW, “The most interesting part of this research was finding out that we could print these scaffolds that contain up to 70% bone by mass! That means the vast majority of these porous scaffolds were made up of native material (which is used clinically), that could be printed in any anatomical shape.”

“Based on the considerable advances that are being made in the biomaterials field, the not-too-distant future may hold the potential for printing out patient-specific replacements grafts made almost entirely of native bone scaffolding.

Brits Grow Ear From Fat

Biloine W. Young • Thu, March 13th, 2014

A team of doctors at Great Ormond Hospital in London are making serious plans to reconstruct an ear with stem cells taken from their patient’s fat. They have already succeeded in growing cartilage in their laboratory and plan to proceed using a technique published in the journal Nanomedicine.

According to James Gallagher, writing for the BBC Health News, the doctors want to treat conditions like microtia, a situation where an ear fails to develop properly, is malformed or is missing altogether.

Microtia is presently treated by physicians taking cartilage from a child’s ribs, sculpting it to make it resemble an ear and implanting it back into the child. The method is far from satisfactory as it requires multiple operations, leaves permanent scarring on the chest and the rib cartilage is said to never fully recover.

The team planning to reconstruct an ear using stem cells intends to take a tiny sample of fat from the child and extract stem cells from it. They plan to place an ear-shaped scaffold in the stem cell mixture so the cells could take on the desired shape and structure. They plan to use chemicals to persuade the stem cells to transform into cartilage cells. The researchers report that they have been able to create the cartilage in the scaffold, but want to do more safety testing before they use the technique on patients.

One of the researchers, Patrizia Ferretti, M.D., told the BBC: "It is really exciting to have the sort of cells that are not tumourogenic, which can go back into the same patient so we don't have the problem of immunosuppression and can do the job you want them to do. It would be the Holy Grail to do this procedure through a single surgery, so decreasing enormously the stress for the children and having a structure that hopefully will be growing as the child grows."

Martin Birchall, M.D. is a surgeon at University College, London, who was involved in the first operations to give patients lab-grown windpipes. He said of the ear project, "If you had something that was truly regenerative, that would be transformative."

Lab Bio-Prints Living Human Cartilage

Biloine W. Young • Fri, May 16th, 2014

In a major step forward researchers have succeeded in creating living, human cartilage that they grew on a laboratory chip. This development brings them closer to their ultimate goal which is creating replacement cartilage for patients with osteoarthritis. The process used bioprinting technology.

Leader of the research group is Rocky Tuan, Ph.D., director of the Center for Cellular and Molecular Engineering at the University of Pittsburgh School of Medicine. He said that creation of the artificial cartilage required three main elements: stem cells, biological factors to help the cells grow into cartilage, and a scaffold to give the tissue its shape. He said that his team’s process involved the extrusion of thin layers of stem cells embedded in a solution that retains its shape and provides the growth factors.

“We essentially speed up the development process by giving the cells everything they need, while creating a scaffold to give the tissue the exact shape and structure that we want, ” Tuan explained.

At present, the researchers are working to combine their 3D printing method with a nanofiber spinning technique they developed earlier. They hope combining the two methods will provide a more robust scaffold and allow them to create artificial cartilage that even more closely resembles natural cartilage. The ultimate vision is to give doctors a tool they can thread through a catheter to print new cartilage right where it’s needed in the patient’s body.

Tuan notes that artificial cartilage built using a patient’s own stem cells could offer enormous therapeutic potential. “We hope that the methods we're developing will really make a difference, both in the study of the disease and, ultimately, in treatments for people with cartilage degeneration or joint injuries, ” he said. “Ideally, we would like to be able to regenerate this tissue so people can avoid having to get a joint replacement, which is a pretty drastic procedure and is unfortunately something that some patients have to go through multiple times."